CODEWITHSUNDEEP
swiftproperty-wrapper
Chris Prince
Chris Prince

Reputation: 7584

Access name of object being wrapped, in Swift property wrapper implementation

I'm using Swift property wrappers to define something like:

@MyWrapper var foo: Int

And in the implementation of the property wrapper, I'd like to access the name of the variable, foo, as a string. Something like this:

@propertyWrapper
public struct MyWrapper<Type> {
  init() {
    // Get access to "foo" -- name of var as String
  }
}

Suggestions?

Upvotes: 21

Views: 1991

Answers (1)

YodagamaHeshan
YodagamaHeshan

Reputation: 6550

To pass variable name to the wrapper; you can use this alternative way.

@propertyWrapper
public struct MyWrapper<Type> {

  var wrappedValue: ... {
  set{.....}
  get{.....}
  }

  init(wrappedValue initialValue: Double, _ nameOfTheVariable: String ) {
      precondition(!nameOfTheVariable.isEmpty)
      //you can access nameOfTheVariable here
  }  
}

then use it like below,

   @MyWrapper("foo") var foo: Int

Note: in the init method mentioning wrappedValue is a must. Unless , It didn't work for me.

(init(wrappedValue initialValue: Double, _ nameOfTheVariable: String ) )

Upvotes: 1

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